Growl for Windows - Growl for Windows is a Windows-compatible version of https://alternativeto.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Notify OSD - Canonicals on-screen-display notification agent, implementing the freedesktop.
AppDynamics - Get real-time insight from your apps using Application Performance Management—how they’re being used, how they’re performing, where they need help.
Notifu - Notifu, a free open source pop-up balloon utility
Zabbix - Track, record, alert and visualize performance and availability of IT resources